Soldiers in the U.S. military can now carry Android-powered smartphones made by Samsung thanks to a recent approval by the U.S. Department of Defense (DOD).

Samsung smartphones running a secure version of Android -- called Knox -- were deemed secure enough for DOD approval, which signals the beginning of a more diverse mobile ecosystem within the U.S. military.

Other versions of Android and Apple's iOS are currently awaiting approval as well. These decisions are expected to be made by the end of May.

There are about 600,000 smartphone users in the DOD. About 470,000 were using BlackBerry devices only, since those were the only smartphones secure enough for such sensitive information.

However, BlackBerry saw some hard times over the past couple of years -- including a major service outage that affected Europe, the Middle East, India, North America and Africa in October 2011 -- and lost significant market share to the likes of Apple and Google's Android operating system.

DOD has since opened up testing of other devices to see if they can be as secure as BlackBerry smartphones. With Samsung and the Knox version of Android on board, others should be approved in time as well.

Even worse. Every time there's an iOS update I have to keep super attention to our Exchange servers so they won't take them down again like the 6.1.1 version did. Android never hurt us at all. One iOS device with shoddy firmware did. Thanks, Apple!